The present invention relates to removable floor panels used for the construction of "clean room" and computer room floors, and more particularly, to a perforated floor panel.
Perforated floor panels are known and have utility in the construction of raised floors in applications requiring that an under floor space be provided. One application is, for example, computer room floors wherein an under floor space is required both for the many electrical cables supplying power to the computers, and a supply air plenum connecting the discharge of an air conditioner and the air intakes at the base of computers housed in the room.
Another application wherein perforated floor panels are particularly suited is for floors in "clean rooms" having a vertical laminar flow ventilating air system wherein the under floor space is utilized as an air return plenum.
It is extremely important in vertical laminar flow clean rooms that a controlled balanced laminar flow of ventilating air be maintained to continuously wash the entire "clean room" with a uniform amount of clean air. If a balanced laminar air flow is not maintained, turbulence and eddys will result which will catch containants and recirculate them throughout the room instead of carrying them out of the room through the return air plenum beneath the floor.
Balancing the air flow in a vertical laminar air flow clean room is generally done by, basically, two different methods:
1. Arranging solid and perforated floor panels making up the floor by trail and error to achieve a pattern of perforated floor panels which provides a balanced laminar flow.
2. Placing dampers to the underside of the perforated panels and adjusting them to allow different volume rates of flow-through individual panels until a balanced air flow is achieved.
Interchanging or shifting perforated and solid floor panels is a primitive way to balance the air flow in a clean room and only approaches laminar flow, but does not attain it because a portion of the floor is formed of solid panels. Usually, it is required that the floor panels are arranged so that the air return side of the room closest to the fans of an air circulating system servicing the room has only solid floor panels while the opposite side has all perforated floor panels. As soon as equipment is installed in the room, it becomes out of balance causing the air at the fan side of the room to cascade across the floor as it flows to the perforated panels, thus, eliminating any semblance of laminar flow.
Dampers, theoretically, provide unlimited adjustment of the amount of air flow passing through the floor so that the floor can be arranged in a checkerboard pattern of solid and perforated floor panels. However, in application, they do not properly perform the function of producing a laminar flow. While the air flow pattern can be balanced by adjusting the dampers, if any equipment housed in the room blocks one perforated panel or one damper is subsequently moved, the flow through the entire floor can be unbalanced. Further, the damper setting can be easily inadvertently altered by cleaning crews when they lift the panel to clean it. Indeed, even a force applied to the floor surface of the panel can distort it sufficiently to cause a change of the damper setting. In addition, dampers are relatively expensive and can be noisy, the noise being a disturbing influence to the concentration of persons performing delicate tasks within the room.